Biological activities and phytochemical constituents of the gray mangrove Avicennia marina (Forssk.) Vierh.

Abstract

In vitro assessment of the antibacteriophage, antibacterial and anticandidal activities as well as cytotoxicity were evaluated for both aqueous and ethanol extracts prepared from roots, cotyledons, leaves and stems of Avicennia marina. Aqueous extracts of both shoots and roots of the seedlings demonstrated antibacteriophage activity using coliphage against Escherichia coli NRRL B-3704, which indicates antiviral activity. Aqueous extracts also exhibited moderate cytotoxicity against the larvae of the brine shrimp Artemia salina, which demonstrates antiplasmodial and antimalarial activities. However, both aqueous and ethanol extracts of various parts of the seedlings lacked antimicrobial activities against eight microbial test strains. On the other hand, irradiation of either seedling parts or plant extracts with long-wave UV radiation elicits immediate phototoxic activity. Investigating the production of growthregulating substances in crude extracts reveals the presence of auxin- and cytokinin-like activities. Phytochemical analysis of ethanol extract of the shoot system indicates the presence of some biologically active metabolites including tannins, flavonoids, sterols, iridoid glycosides and organic acids. Alkaloids and saponins were not present in the extracts, which means no toxicity. The potential medicinal value and phytochemical prospects of the gray mangrove grown on the Red Sea coastline of Egypt are discussed.

KEY WORDS: antibacteriophage activity, phototoxic antimicrobials, cytotoxicity, growth regulators, Gulf of Aqaba, Red Sea.

Egyptian Journal of Botany Vol.5 2003: 62-69